Film processing

1. Dental X-Ray Film And
Film Processing
Kituzi E. Mshindi
Faith Surtan
Undisa Euro

2. DENTAL X-RAY FILM
Kituzi E. Mshindi

3. Dental x-ray film
Dental X-ray film serves as a recording medium or image receptor.
Images are recorded on the dental X-ray film when the film is exposed to a stimulus
specifically energy in the form of x-radiation or light.

4. X-ray Film Composition;
Film base
Adhesive layer
Emulsion or vehicle layer
Protective layer

5. Film Base
The film base is a flexible piece of polyester plastic that measures 0.2 mm (.007
inch) thick(polyester polyethylene terephthalate)
It is constructed to withstand heat, moisture, and chemical exposure.
The film base is transparent and exhibits a slight blue tint that is used to emphasize
contrast and enhance image quality.
The film base provides a stable support and strength for the delicate emulsion.
It is coated on both sides thus it is referred to as a double emulsion, in this case less
radiation is required than with the single- sided emulsion film.

6. Ideal properties of a base material
Structural support for the fragile emulsion
Low heat absorption
Flexible, thick and strong
Dimensionally stable
Non-flammable

7. Adhesive Layer
Its also called subbing layer or substratum layer.
is a thin layer of adhesive material that covers both sides of the film base.
It is added to the film base before the emulsion is applied and serves to attach the
emulsion to the base during coating stage and processing.
It provides a uniform surface over which emulsion can be coated uniformly

8. Emulsion Layer;
The film emulsion is a coating attached to both sides of the film base by the
adhesive layer to give the film greater sensitivity to X-radiation.
It consist of a homogenous mixture of silver halide crystals and vehicle matrix
(gelatin)
90-99% is AgBr and about 1-10% Agl
Agl produce an emulsion of much sensitivity than pure Ag emulsion
It also contains traces of sulfur

9. …..emulsion layer;
Silver halide crystals can be tabular granular polyhedral or irregular in shape.
Grain size and distribution affects the speed, contrast and grainniness of the film i.e,
-the bigger the average grain size the higher the speed of the film,
-the more the grain distribution in the film the lower the contrast
-the bigger the crystal the high the graininess of the film.
Gelatin;
-it is used as a suspending medium and a binding agent for the silver halide particles
-During film processing, it absorbs the processing solutions and allows the chemicals
to react with the silver halide crystals.

10. Protective Layer
it is a thin transparent coating placed over the emulsion.
It protects the emulsion surface from manipulation as well as mechanical and
processing damage.

11. Crosssectionofadoubleemulsionradiographicfilm

12. Types of X-ray film
1) According to their USES.
i. Intraoral films;
a) periapical films
No. 0 – children
No.1 -anterior adult
No.2 – standard adult
b). Occlusal films
c).bitewing films
ii.Extraoral films

13. …types of x-ray film
2. According to speed
i. slow film
-speed A
-speed B
-speed C
ii. Fast film
D-ultra speed
E-ekta speed
F-ultra ekta speed
iii. Hyper speed G
3. According to emulsion layer
-single coated
-double coated
4. According to packaging
-single film packet
-double film packet

14. ….types of x-ray film
5. According to action/screen
i. Direct action/non-screen films
-they are used in intraoral radiographs with need for excellent image qualities & fine
anatomic details
- 3 sizes are commonly used (31*41mm for periapicals, 22*35 for bitewings,
57*76mm for occlusals)
- Film packet contains an outer wrapper, the film, sheet of lead foil, protective black
paper.

15. …types of x-ray film
ii. Indirect action films
- Film/screen combinations are used as image detectors because of the reduced
dose of radiation to the patient, especially when very fine details are not needed.
-they are used in;
- Oblique lateral radiographs
- All skull radiographs
- Dental panoramic tomographs
- All routine medical radiographs
- Intraoral vertex occlusal radiographs

16. INTRAORAL FILMS
They are placed inside the mouth during X-ray exposure.
An intraoral film is used to examine the teeth
and supporting structures.

17. INTRAORALFILMPACKAGING
i. X-ray Film:
A film packet may contain one film (one –film packet) or two films (two-films packet).
ii. Paper Film Wrapper
The paper film wrapper within the film packet is a black paper protective sheet that
covers the film and shields the film from light.
iii. Lead Foil Sheet
The lead foil sheet is a single piece of lead foil that is found within the film packet
and is located behind the film wrapped in black protective paper.
The thin lead foil sheet is positioned behind the film to shield the film from back-
scattered (secondary) radiation that results in film fog.

18. INTRAORALFILMPACKAGING
iv. Outer Package wrapping:
-it is a soft vinyl or paper wrapper that hermetically seals the film packet, protective black paper, and lead
foil sheet.
- This outer wrapper serves to protect the film from exposure to light and saliva.
-The outer wrapper of the film packet has two sides: tube side and label side.
Tube side: is solid white and has a raised bump in one corner that corresponds to the identification dot on
the X-ray film.
- When placed in the mouth, the white side (tube side) of the film packet must face the teeth and the
tubehead.
Label side:
it has a flap that is used to open the film packet to remove the film prior to processing. The label side is
color coded to identify films outside of the plastic packaging container; color codes are used to distinguish
between one-film and two-film packets and between film speeds.
When placed in the mouth, the color coded side (label side) of the packet must face the tongue for lower
teeth and face the palate for upper teeth.

19. Types of intraoral films
Three types of intraoral films are available:
- periapical film.
- bitewing film.
- occlusal film.
Periapical Film
-it is used to examine the entire tooth (crown and root) and supporting bone.
-The term periapical is derived from the Greek word peri meaning around and the Latin word apex
meaning the terminal end of a tooth root.
-As the term suggests, this type of film shows the tip of the tooth root and surrounding structures as
well as the crow

20. …types of intraoral films
Bitewing Film ;
-The bitewing film is used to examine the crowns of both the maxillary (upper) and
mandibular (lower) teeth on one film.
-The bitewing film is particularly useful in examining the Interproximal surfaces, or
adjacent tooth surfaces.
-The bitewing film has a "wing", or tab, attached to the tube side of the film.
-The patient "bites" on the "wing" to stabilize the film, hence the term bitewing.
-Bitewing films may be purchased with tabs attached to the film or may be
constructed from a periapical film and bitewing loop.

21. …types of intraoral films
Occlusal Film ;
-The occlusal film is used for examination of large areas of the maxilla (upper jaw) or
mandible (lower jaw).
-The occlusal film is so named because the patient "occludes" or bites on the entire
film.
-The occlusal film is larger than periapical or
bitewing films.

22. Intraoral Film Sizes
Intraoral film is manufactured in sizes to accommodate the varying mouth sizes of children,
adolescents and adults.
The larger the number the larger the size of the film.
Different sizes of film are used with periapical, bitewing and occlusal exposure.
Intraoral film packets come in five basic sizes:
- child size no. 0,
- narrow anterior film no. 1,
- size no. 2,
- occlusal film packets no. 4
- preformed long bitewing films no. 3
The intraoral film packets are light tight and resistant to salivary seepage ,they also have
some degree of flexibility and are easy to open in the darkroom.

23. ...intraoralFilmSizes
Periapical Film
There are three sizes ie 0, 1 and 2 :
Size 0: is the smallest intraoral film
is used for small children (22 × 35 mm).
Size 1: is used primarily to examine the anterior teeth in adults (24 × 40 mm).
Size 2: is also known as the standard film,
is used to examine the anterior and posterior teeth in adults (32 × 41 mm).

24. ...intraoralFilmSizes
Bitewing Film
There are four sizes ie 0, 1, 2 and 3.
With the exception of the size 3 film,the size and shape of the bitewing film are identical to
the size and shape of the periapical film.
Size 0: is used to examine the posterior teeth in small children.
Size 1: is used to examine the posterior teeth in children.
When positioned vertically, it can be used to examine the anterior teeth in adults.
Size 2: is used to examine the posterior teeth in adults.
This is the most frequently used bitewing film.
Size 3: This film is longer and narrower than the standard
Size 2 film and is used only for bitewings, this bitewing film shows all of the posterior teeth
on one side of the arch in one radiograph.

25. ...intraoralFilmSizes
Occlusal Film;
-is the largest intraoral film and
-is almost four times as large as a standard Size 2 periapical film (57 × 76 mm).
- Size 4: This occlusal film is used to show large areas of the upper or lower jaw.

26. IntraoralFilmSpeed(Sensitivity)
 Film speed refers to the amount of radiation required to produce a radiograph of
standard density.
 it is determined by the following:
- The size of the silver halide crystals.
- The thickness of the emulsion.
- The presence of special radiosensitive dyes.

27. ....IntraoralFilmSpeed(Sensitivity)
Film Speed
More sensitive films require less mAs and are said to have greater film speed
they are fast films.
Slow films require more mAs and are less sensitive to radiation.
The size of the silver bromide crystals is the main factor in determining the film
speed, the larger the crystals the faster the film.
Slow film at 65 kVp and 10 mA would take an average exposure time of about
3 seconds per film and the fast film about 1/3 of second of exposure per film.
The intermediate speed film take about 1½ second.
Film speed determined how much radiation and how much exposure time are
necessary to produce an image on a film.
X-ray films are given speed ratings ranging from A speed (the slowest) to F
speed (the fastest). Only D-speed film and E-speed film are used for intraoral
radiography.

28. KODAKFILMSPEED
Only D-speed film (Kodak Ultra-speed) and E-speed film (Kodak Ektaspeed) are used
for intraoral radiographs.
The American Dental Association (ADA) currently recommend the use of E-speed
film.
E-speed film requires one-half the exposure time of D-speed film.
E-speed film is a faster film than D-speed because of the larger crystals and the
increased amount of silver bromide in emulsion.

29. Extraoral Film.
An extraoral film is one that is placed outside of the mouth during x-ray exposure. eg
panoramic film shows a panoramic (wide) view of the upper and lower jaws on a
single radiograph, whereas a
cephalometric film exhibits the bony and soft tissue areas of the facial profile.
General X-rays- Chest, PA Skull X-rays

30. EXTRAORALFILMTYPES:
Two types of film may be used in extraoral radiography:
Screen film.
The majority of extraoral films are screen films.
A screen films is placed between two INTENSIFYING SCREENS in a CASSETTE HOLDER.
Screen films are sensitive to FLOURESCENT LIGHT rather than direct exposure to x-
radiation.
Nonscreen film:
-it does not require the use of screens.
-The emulsion is sensitive to DIRECT X-RAY EXPOSURE.

31. EXTRAORALFILMEQUIPMENT:
INTENSIFYING SCREEN
An intensifying screen is a device that transfers x-ray energy into visible light; the
visible light, in turn, exposes the screen film. With the use of intensifying screen, less
radiation is required to expose a screen film, and the patient is exposed to less
radiation.
An intensifying screen is a smooth plastic sheet coated with minute fluorescent
crystal known as phosphors.
When exposed to x-ray, the phosphors fluoresce and emit visible light in the blue or
green spectrum; the emitted light then exposes the film.

32. Phosphors
Phosphors are substances that display luminescence (glows) :- eg dashboard of a car , old
monitors, neon lights, flourescent bulbs, CRT displays
Conventional screens have calcium tungstate phosphors that emit blue light and are used for
blue-sensitive films (Kodak X-Omat and Ektamat films).
The newer rare earth screens have phosphors that are not commonly found in the earth
(hence the name rare earth) and emit green light
Rare earth intensifying screens are more efficient than calcium tungstate intensifying screens
at converting x-ray into light, require less x-ray exposure and are considered faster which
means less exposure to x-radiation for the patient.
Rare earth intensifying screens (Kodak Lanex Regular and Medium screens) are designed for
use with green-sensitive films (Kodak Ortho and T-Mat films).

33. Rare earth intensifying screens
The newer rare earth screens have phosphors that are not commonly found in the earth
(hence the name rare earth)and emit green light.
Rare earth intensifying screens are more efficient than calcium tungstate intensifying screens
at converting x-ray into light.
As a result, rare earth screens require less x-ray exposure than calcium tungstate screens and
are considered faster. The use of rare earth screen means less exposure to x-radiation for the
patient.
Rare earth intensifying screens (Kodak Lanex Regular and Medium screens) are designed for
use with green-sensitive films (Kodak Ortho and T-Mat films), whereas
Conventional screens (Kodak X-Omatic Regular screens and Ektamat films) are used for blue-
sensitive films (calcium tungstate screens )

34. CASSETTEHOLDERS
1. A cassette holder is a device that holds the
a. extraoral screen film and the
b. intensifying screens.
c. It has a front cover which is placed so that it faces the tube head and is usually
made of plastic to permit the passage of the x-ray beam and
d. a back cover which is made of heavy metal and serves to reduce scatter radiation.
A cassette holder may be flexible or rigid; most are rigid with the exception of the
panoramic cassette holder, which may be flexible.

35. Duplicating films
Duplication of the radiographs is essential in recent years from the litigation point of view
and also to protect ourselves.
- The defendant-dentists records are of the almost importance.
it requires a few additions to normal darkroom equipment, such as duplicating film,
photographic printing frame, appropriate size film hangers a light source (ultraviolet).
- All size of the radiographic films are duplicated by commercially available duplicating
devices.
- Radiographic duplicating film is available in 8 × 10 or 5 × 12 inches sheets and individually
wrapped periapical size duplicating film.
- The emulsion on duplicating film is present only on one side of the film.
- The emulsion side appears dull while the nonemulsion side appears shiny.
- The duplicating film has a direct positive emulsion, therefore, if more film density is
needed, the exposure time is shortened and if decreased film density is required, the
exposure time is increased.
-This is the opposite of time required for exposing dental film to X-rays.
-Duplicating films have no orientation dot for identification, the film must be labeled as
right and left.

36. Original Duplicate
If done properly, a duplicate film will provide most of the
diagnostic information needed (see below). However, duplicate
films are never as good as the original.

37. Original Duplicate
If not done properly, duplicate films will be of little value in
trying to make a diagnosis. Films should always be removed
from film mounts before duplicating in order to insure tight
contact between the original and duplicate films. Lack of tight
contact produced the duplicate film below.

38. DENTAL X-RAY FILM
PROCESSING
FAITH SURTAN

39. CONTENTS
INTRODUCTION
FILM PROCESSING STEPS
FILM PROCESSING SOLUTIONS
PROCESSING ROOM
EQUIPMENT REQUIREMENTS
GENERAL SAFETY RULES OF DARK ROOM
MOUNTING OF RADIOGRAPHS
WASTE MANAGEMENT OF DARK ROOM

40. INTRODUCTION
Film processing refers to a series of steps that produce a visible permanent image
on a dental radiograph.
AIMS OF PROCESSING
 To convert the latent image (invisible) on the film into a visible image.
 To preserve the visible image so that it is permanent and does not disappear from
the dental radiograph

41. PROCESSING METHODS
A) Manual Processing:
Three methods
I. Time temperature method
II. Modified time temperature method
III. Visual method
B) Automatic Processing
C) Day Light Processing
D) Self Developing Films

42. MANUAL FILM PROCESSING STEPS
Consists of following five steps:
i. Development
ii. Rinsing
iii. Fixing
iv. Washing
v. Drying

43. 1. DEVELOPMENT
A chemical solution developer is used in the development process.
Development is a chemical process that amplifies the latent image by a factor of
millions (about 100,000,000) to form a visible silver pattern.
The basic reaction is reduction (addition of an electron) of the silver ion, which
changes it into black metallic silver.
Ag+ + electron = Ag.
(Silver ion in crystal containing latent image) + (electron from developer) = silver
atoms image

44. Purpose Of Developer
The exposed, energized silver halide
crystals chemically turns into black
metallic silver.
Softens the film emulsion during the
process.

45. 2. RINSING
A continuous, gentle rinsing for 30 sec in water is necessary after developing
i. To dilute the developer and slow the development process
ii. To remove alkali activator.

46. 3.FIXING
A chemical solution fixer is used in the fixing process.
Purpose of Fixer
-Remove the unexposed, unenergized silver halide crystals from the
film emulsion.
-Hardens the film emulsion during the process.

47. 4.WASHING
Necessary to thoroughly remove all the excess chemicals from the emulsion.

48. 5. DRYING
Should be air dried at room temperature in a dust free area.
Must be completely dried before they can be handled for mounting and viewing.

49. Time temperature method
1. Before processing check the levels of developer and fixer solution.
If the solution level is low add fresh solution.
Never add water to raise the level of the solution, as it dilutes the strength of
chemicals.
2. Stir the processing solution with a stirring rod or paddle. (Stirring the solution mixes
the chemicals and regularizes the temperature of the solution)
3. Check the temperature of the developer solution.(The optimum temperature for
developer is between 343 -398).
If the temperature of the developer solution is outside this range circulating water
tap must be regularized to adjust the temp and sufficient time must be allowed to
reach the correct temperature.

50. 4. Close and lock the dark room, turn off the overhead white light and turn on the
safelight.
5. Remove the exposed film from its lightproof packet, using only safe light
illumination.
6. Hold the film only from their edges.
7. Clip the bare film to the hanger clip (1 film to a single clip).
8. Based on the temperature of developer solution and the instruction of
manufacture, set the timer.
A time-temperature chart is used to determine the time.

51. 9. Immerse the film hangers with the films into developer solution.
Film must not contact one another or the sides of the processing tanks during development.
10. Gently agitate the film hanger up and down, Several times to prevent air bubbles from
dinging to the film.
11. Hang the film hanger on the edge of the insert tank and make sure that all the films
immersed in the developer.
12. Activate the timer and cover the processing tank.
13. When the timer goes off, take cover off the processing tank, remove the film hanger with
film from the developer solution and place it in the circulating water of the rinsing tank.
14. Further surface moisture is removed by gently shaking off the excess water form the film
and the hanger.
15. Dry the film in circulating, moderately warm air.
16. Remove the dry radiographs from the film hangers and use a view box to examine the
radiographs and place then in an envelope labeled with patients name and date of exposure.

52. Modified time temperature method
In this method depending upon the temperature of solution, the developing time is
divided on daily basis.
A table or a chart can be prepared by specifying developing time for a range of
daytime temperature.
Advantage :
 Temperature need not be maintained at particular level and at the same time
consistent image quality can be gained.
Disadvantage :
 For every brand of developer separate time temperature chart should be prepared

53. Visual method
In this method the exposed x-ray film is immersed in developing solution; For about
10 sec and then removed and observed in the safe light.
If adequate images have been obtained then it is put for rinsing, otherwise re-
inserted in the developing solution till adequate image is obtained.
Disadvantage :
 This method is highly objective in nature and doesn’t give consistent quality.

54. AUTOMATIC PROCESSING
1. Prepare darkroom; if daylight loader is not part of automatic processor.
2. Close and lock the door of darkroom.
3. Turn off the overhead white light, and turn on the safelight.
4. For intraoral films, carefully unwrap each exposed film over a clean working
surface.
For extra-oral films carefully remove the film from the cassette.
5. Handle all the films by the edges only.

55. 6. Insert each unwrapped film into the film feed slot of the processor, one at a time.
7. Allow at-least 10 sec between the insertion of each film.
8. Do not turn the films sideways or insert too quickly, they will overlap; overlapped
films results in non diagnostic radiographs.
9. After films are inserted, allow 4-6 min for automated processing to occur.
10. Retrieve the processed radiographs from the film recovery slot on the outside of
the automatic processor.

56. ADVANTAGES
i. Time saving .
ii. Constant film quality is achieved, due to fixed processing cycles.
iii. Need for dark room is eliminated.
iv. Less floor space is required.
v. Chemicals can be replenished automatically by machine.
vi. Large number of films can be processed continuously

57. DISADVANTAGES
I. Equipment is relatively expensive.
II. Strict maintenance and regular change is required, dirty rollers produce marked
films.
III. Films may get lost in the tank

58. Day Light Processing Method
Any processing method that doesn’t need a dark room is called as daylight processing
method.
Both manual and automatic processing can be executed in this manner.
Manual day light processing involves stripping the film inside a light proof pouch.
Then processing steps are carried out manually as usual but in daylight.
If an automatic processor has a daylight-loading chamber and since the entire
assembly is enclosed in a light proof container, it also can be called a daylight
processing method.
Elimination of need for a darkroom is the only advantage in this method.

59. SELF DEVELOPING FILMS
Self-developing films are an alternative.
The x-ray film is presented in a special sachet, containing developer and fixer.
Following exposure the developer tab is pulled, unveiling developer solution, which is
milked down towards the film and massaged around it gently.
After about 15 seconds, the fixer tab is pulled to release fixer solution, which is
similarly milked down to the film.
After fixing, the used chemicals are discarded and the film is rinsed thoroughly under
running water about 10 minutes.

60. Advantages :
o No dark room or processing facilities are needed.
o Time saving.
Disadvantages :
o Poor over all image quality.
o Image deteriorates rapidly over time.
o No lead foil inside the film hence less flexible and can be easily bent .
o These films are difficult to use in position holders.
o Relatively expensive

61. FILM PROCESSING SOLUTIONS
Obtained in following forms :
i) Powder
ii) Ready to use liquid
iii) Liquid concentrate
Both powder and liquid concentrate forms must be mixed with distilled water.
Liquid concentrate form is popular-easy to mix and occupies little storage space.
Fresh chemical solutions produce the best radiographs.
To Maintain Freshness:
i)Solutions must be replenished daily.
ii)Must be changed after every 3-4weeks.
Two special chemical solutions are necessary for film processing:
i) Developer
ii) Fixer

62. DEVELOPING SOLUTION:
i) Developer
ii) Preservative
iii) Accelerator
iv) Restainer
FIXER SOLUTION:
i) Fixing agent
ii) Preservative
iii) Acidifier
iv) Hardening agent

63. DEVELOPING SOLUTION
Developing solution convert the exposed silver halide crystals into black metallic
silver grains.
This process begins at latent image sites.
At latent image site, electrons from the developing agents are conducted into the
silver halide crystals and reduces the constitute silver ion to solid grains of metallic
silver.
Unexposed silver halide crystals, are unaffected during the time of reduction of
exposed crystals into metallic silver.

64. 2 components of developing solution:
i) Phenidone
- First electron donor
-This electron transfer generates the oxidized form of phenidone.
ii) Hydroquinone
- Provides an electron, to reduce the oxidized phenidone back to its active state, so
that it can continue to reduce silver halide grains to metallic silver.

65. ACTIVATOR
Alkaline in nature
- Developing agents are active only at alkaline pH values( high pH) .
- Achieved by adding alkali compounds
a.) Sodium or potassium hydroxide
b.) Buffer-sodium bicarbonate
- This causes the gelatin to swell so that developing agents easily diffuse with
emulsion.

66. PRESERVATIVE
Sodium sulfite (antioxidant)
o Prevents oxidation of developing agents
o Preservative is added with ‘brown oxidized developer’. This makes the solution
colourless.

67. RESTAINER
Potassium bromide and Benzatriazole.
o Prevents the developement of unexposed silver halide crystals
o It depresses the reduction of both exposed and unexposed silver halide crystals but
are more effective in reduction of unexposed silver halide crystals.
o The restainer acts as ‘antifog agent’ and increases the contrast.

68. DEVELOPER REPLENISHER
During normal course of film processing:
i)Phenidone and hydroquinone are consumed from solution.
ii)Bromide ions and byproducts are released into the solution
iii)Developer solution gets inactivated by exposure of oxygen.
These actions produces a seasoned solution.
Hence developer sol must be replenished daily to prolong the life of seasoned
solution
Recommended amount-30l of developer solution.

69. FIXING SOLUTION
I)CLEARING AGENT
Ammonium thiosulfate
Dissolves and removes the unexposed silver halide grains. Ammonium thiosulfate
forms a stable, water soluble complex with silver ions (silver thiosulfate complex),
which then diffuses from the emulsion.
Thiosulfate does not have a rapid effect on the metallic silver grains in the film
emulsion
But excessive fixation results in loss of film density, because the grains of silver slowly
dissolve in the acetic acid of fixing solution.

70. ACIDIFIER
Contains an acetic acid buffer system (PH 4-4.5)
This acidic pH required for
a.) Good diffusion of thiosulfate into the emulsion
b.) Silver thiosulfate complex out of the emulsion.
Inactivate any carryover developing agents in the film emulsion, hence blocks the
further development of any unexposed crystals.

71. PRESERVATIVE
Sodium sulfite
Prevents oxidation of clearing agents as they are unstable in the acidic environment
of fixing solution.
Binds with any colored oxidized developer carried over into the fixing solution, and
removed it from the solution.
This prevents oxidized developer from staining the film.

72. HARDENER
Aluminium sulfate
This complexes with gelatin and hardens the gelatin during fixing process.
Reduces the swelling of emulsion
↓
Lessens mechanical damage to the emulsion
↓
Limits water absorption
↓
Shortening drying time.

73. PROCESSING ROOM

74. PROCESSING ROOM REQUIREMENTS
A well planned dark room makes the processing easier, which should be of atleast 4 ×
5 feet (1.2 × 1.5 m ).
Characteristics of darkroom :
i) Convenient location and adequate size
ii) Ample working space with adequate storage
iii) Lighting
iv) Temperature and humidity controlled
v) Darkroom plumbing
vi) Miscellaneous

75. …processing room
LOCATION-Darkroom should be located near the area where the x-ray units are
installed.
SIZE-darkroom size is determined by the following factors:
o Volume of radiographs processed
o Number of persons using the room.
WORKING SPACE ;
o Adequate counter area where films can be unwrapped.
o A clean, organized work area is essential which should be free of processing
chemicals, water, dust, and debris.
STORAGE SPACE -Adequate space for storage for chemical processing solutions,
film cassettes etc.

76. …processing room
LIGHTING –
The room must be completely dark and must exclude all visible light.
Any leaks of white light in the darkroom causes film fog.
Two types of lighting are essential in darkroom.
i)Room lighting (white illumination)
ii)Safe lighting.
I. Room lighting :
Incandescent room lighting is required to perform task such as cleaning, stocking
materials and mixing chemicals, this is not associated with the act of processing films.

77. II. Safe lighting :
Special kind of lighting of relatively long wavelength and low intensity illumination that
does not rapidly affect open film but permits one to see well enough to work in the
area.
To minimize the fogging effect of prolonged exposure, the safe light should have a 15
W bulb and a safe light filter(red GBX-2 filter ).
It should be mounted atleast 4 feet (1.2 meters) above the surface where films are
handled.

78. TEMPERATURE AND HUMIDITY - Should be controlled to prevent film damage.
Room temp of 70 degree F is recommended ; if exceeds 90 degree F,film fog results.
Humidity level of between 50 and 70 percent should be maintained; when too high,
film emulsion does not dry; when too low, static electricity becomes a problem and
causes film artifacts.
DARKROOM PLUMBING-
Must include both hot and cold running water along with mixing valves to adjust
the water temperature in the processing tanks with utility sink.
MISCELLANEOUS REQUIREMENTS:
i)Wastebasket for disposal of all film wrappings.
ii)x-ray view box used to examine radiographs

79. EQUIPMENT REQUIREMENTS
• Manual Processing tanks
• Timer
• Thermometer
• Film hangers
• Miscellaneous equipments

80. MANUAL PROCESSING TANK
Has 2 insert tanks and 1 master tank
Constructed of stainless steel
Does not react with processing solutions and easy to clean.
Practical size for a master tank in dental office is about 20 × 25 cm
1. INSERT TANKS:
2 removable 1-gallon ( 3.8 L) insert tanks hold the developer and fixer solutions,
placed in master tank.
Developer solution is placed on the left and fixer solution placed on right in the
master tank.
Water in master tank seperates the two insert tanks.

81. THE END

82. 2. MASTER TANK:
Filled with circulating water.
An overflow pipe is used to control the water level in the master tank.

83. TIMER
A timer is use to signal the radiographer that the films must be removed from the
current processing solution.
Development time depends on the temperature of the developer solution.

84. THERMOMETER
Used to determine the temperature of developer solution;
Optimum temp is 68 degree F, below 60 degree F chemical works too slowely,
results in under development;
Above 80 F chemical works too rapidly, will cause film fog.
Floating thermometer or one that is clipped to the side of the developer tank may be
used.
Temperature of developer sol, determine the development time.

85. FILM HANGERS
Also known as processing hangers.
Device equipped with clips used to hold films during processing.
Made up of stainless steel.
Available in various sizes and can hold upto 20 intraoral films.

86. MISCELLANEOUS EQUIPMENTS
i) Stirring rods-made up of plastic or glass use to stirr the developer an fixer solutions,
and equalizes the temperature of the solutions.
ii) Plastic apron-use to protect clothing during the processing of films and mixing of
chemicals.

87. AUTOMATIC PROCESSOR
Uses a roller transport system
PROCESSOR HOUSING: -Encases all the the component parts of the automatic
processor.
FILM FEED SLOT: -Opening on the outside of the processor housing used to insert
unwrapped films into the automatic processor.
ROLLER FILM TRANSPORTER: - System of rollers ( propelled by motor driven gears and
belts) used to move the film rapidly through the developer, fixer, water, and drying
compartments.
Rollers produces wrining action that removes the excess solution from the emulsion.

89. DEVELOPER COMPARTMENT
Holds the developer solution.
Developing solution is specially formulated for automatic processor and different from
developing solution used in manual processing.
A hardening chemical ‘glutaraldehyde’ is added to the conventional manual processing
developing solution, to prevent the emulsion from softening and sticking to the solution.
Sulfate compounds are also added to the manual processing developer, to minimize the
swelling of the emulsion, so that the films can be transported by the roller uniformly.
Because the total processing time is reduced in automatic processing, the chemical
concentration and temperature of the developing solutions must be increased.

90. FIXING COMPARTMENT
Holds fixer solution
Film directly transfer to fixer from developer without rinsing step.
In fixer solution, the film is rapidly fixed and then hardened.
Fixing solution is Specially formulated for automatic processor and different from
fixing solution used in manual processing.
Fixing solution for automatic processor is a highly concentrated chemical solution,
that contains additional hardening agents.

91. WATER COMPARTMENT: Holds circulating water, used to wash the films after fixation.
DRYING CHAMBERS: Holds heated air, used to dry wet film.
FILM RECOVERY SLOT: Opening on the outside of the processor housing, where the
dry, processed radiograph emerges from the automatic processor.

93. Mounting of
radiographs
Euro Undisa

94. Film-based radiographs must be preserved and maintained in a satisfactory condition.
Periapical, interproximal and occlusal films best handled and stored in a film mount
The operator can handle them with greater ease, and there is less chance of
damaging the emulsion

96. Mounts are made of plastic or cardboard and may have a clear plastic
window that covers and protects the film.
However, the window may have scratches or imperfections that interfere
with radiographic interpretation.
The operator can arrange several films from the same individual in a film mount
in the proper anatomic relationship.
This facilitates correlation of the clinical and radiographic examinations.
Opaque mounts are best because they prevent stray light from the view box from
reaching the viewer's eyes
The preferred method of positioning periapical and occlusal films in the film
mount is to arrange them so that the images of the teeth are in the anatomic
position and have the same relationship to the viewer as when the viewer faces the
patient.

97. The radiographs of the teeth in the right quadrants should be placed in
the left side of the mount, and the radiographs of the teeth of the left
quadrants should be placed in the right side.
This system, advocated by the American Dental Association, allows the
examiner’s gaze to shift from radiograph to tooth without crossing the
midline
The alternative arrangement, with the images of the right quadrant on
the right side of the mount and the images of the left quadrant on
the left side, is not recommended

98. Processingerrors
May occur due to various reasons such as:
Time and temperature errors
Chemical contamination errors
Film handling errors
Lighting errors
These errors result in radiographs that are not diagnostic and hence necessitate
additional exposure to patient.
The following photographs show these errors

111. Management of wastes in the dark
room
Although dental radiographic waste constitutes only a small potential hazard, it
should be discarded properly.
The primary ingredient of concern in processing solutions is the dissolved silver found
in used fixer.
Another material of concern is the lead foil found in film packets

112. SAFETY IN THE DARKROOM
SAFETY EQUIPMENT
Inventory your safety equipment before you begin. At a minimum, the darkroom should have
the following items:
• Fire extinguisher
• Spill Kit(s): with signage showing their location
• Safety goggles, enough for each person using the darkroom
• Nitrile, Neoprene (best for acids/bases) or Rubber Gloves
• Tongs
• Hazardous waste handling & pickup info
• Darkroom Safety Guide & Laboratory Safety Manu

113. Eye Protection
All persons in the darkroom (including visitors) must wear safety glasses at all times,
even when not performing a chemical operation. Safety goggles, not safety glasses,
shall be worn whenever chemicals are being poured.
Gloves
Nitrile gloves should be worn at all times when working near chemicals. Latex gloves

114. Do not provide reliable protection because they tend leak easily. Check to ensure
there
are no cracks or small holes in gloves before each use. Prior to leaving the work area,
gloves should be removed to prevent the spread of chemicals.
Only gloves approved for the use with darkroom chemicals shall be used.

115. Clothing
As in any chemical area, clothing in the darkroom should offer protection from
splashes and spills.
Clothing should be easily removable in case of accident.
High-heeled, sandals, open-toed shoes or shoes made of woven material should not
be worn.
Shorts and miniskirts are also inappropriate when working near chemicals.

116. CHEMICAL SAFETY
CHEMICAL INVENTORY: The dark room supervisor is responsible for
determining what chemicals are present in the darkroom
ORDER ONLY WHAT YOU NEED
Before ordering new chemicals, review your current inventory and
use those chemicals first.
Chemicals in large containers that are not used frequently can be
rendered useless in time by contamination or degradation.

117. HANDLING DARKROOM CHEMICALS
• ALWAYS use a water rinse between developer and stop bath
• ALWAYS discard stop bath solutions that have been contaminated with developer.
• ALWAYS add acids to water, not water to acids.
• ALWAYS cover all baths when not in use (to control release of toxic vapours)

118. STORING CHEMICALS
Storing chemicals properly includes:
• proper and clear labelling
• write date of arrival and
• proper placement of the chemical bottles (off the floor) in secondary containers
• compatible storage containers
Improperly stored chemicals can result in the following dangerous conditions:
• Release of potentially toxic vapors
• Degraded containers that allow chemicals to become contaminated.

119. • Degraded containers releasing vapours that can affect the integrity of
nearby containers.
• Degraded labels that result in generation of unknowns.
Proper storage of chemicals means:
Initials of the Responsible Party should be written on all containers.
• Older chemicals should be used first.
• Chemicals must be properly segregated by hazard type.
• All containers must have lids on at all times (except when
pouring).
• Chemicals should never be stored above eye level.

120. CHEMICALWASTEDISPOSAL
All spent silver fixer is to be poured into the Silver Recovery
Processing Unit, located on the floor in the darkroom.
This unit is connected to the regular sink disposal drain that goes
to the sewer
The filter in the silver recovery unit removes silver from the
fixer and must get changed once per year, based on the current
estimated amount of fixer running through it per year.
Safety staff coordinate the changing of the filter with the unit’s
manufacturer.

121. PRACTICE GOOD HOUSEKEEPING
A clean darkroom is generally a safe darkroom. Don’t let trash accumulate, clean the
table tops and sweep the floors on a regular basis.
All chemicals shall be stored and labelled appropriately. Secondary containers should
be placed under all chemicals in storage.
CHEMICAL ALTERNATIVES
There are less-hazardous substitutes for hazardous chemicals used in darkrooms that
can be substituted satisfactorily in many cases.
Chemical/Alternatives:
- Developer / Phenidone
- Stop Bath / Dilute solution of acetic acid (rather than concentrated acetic acid)

122. SPILLPROCEDURES

123. Minor Spills
For minor spills: spills less than 1 litre
Use the Spill Kit provided by Environmental Safety.
Begin the clean up immediately by using the proper personal protective equipment
(PPE) such as gloves, goggles, etc.
1.Use the chemical absorbent grey pads provided in the Spill Kit. Never use paper
towels on an acid spill; the resulting chemical reaction has the potential of causing a
fire.
2.Allow the spilled chemical to absorb into the grey pad.
3.Place the wet pad (spill debris) into the ziplock bag provided in the Spill Kit.
4.Wipe down the contaminated surface with soapy water and a sponge and place all
debris (gloves too) used in the Ziplock bag.
5.Seal the bag and label it with a “Laboratory Waste Tag” provided in the Spill Kit

124. In the event of a MAJOR chemical spill:
A major chemical spill is any spill involving more than 1 litre of chemicals, an unknown
chemical or a small quantity of a high hazard chemical.
Follow the instructions below for a Major Spill:
1. Protect yourself and others by evacuating the room
2. If the spill is spreading, evacuate the floor and/or building
3. From a safe place, report the spill
4. If you can, put up a “Spill in Progress. Do Not Enter” sign & limit access to the spill area
5.Stand by from a safe place until help arrives. Emergency personnel will need information
from you regarding the spill.